Generally, a computer has a processor, memory, monitor, keyboard, and a pointing device, often called a "mouse". The mouse may be an external mouse or an internal mouse, i.e., one built into the keyboard. Some computers, particularly some notebook computers, have two internal mice: (1) a strain gage mouse and (2) a touch pad mouse. In conventional computers that have two mice, one is treated as controlling or primary, i.e., the computer normally accepts only its input signals. The strain gage mouse is usually the primary mouse and the touch pad mouse is usually the secondary mouse. Each of the primary and secondary mice has its own separate electronics, but they share the mouse button switches, the actuation of which enables the user to perform a function such as placing a cursor at a particular location or selecting a portion of text in a particular document.
Currently, computers that have two mice do not allow a user to seamlessly use either mouse, because the actuation of one of the shared mouse buttons does not identify which mouse should have its input signals accepted. As a result, currently, the user must preselect through the SETUP program only one of the two mice, as the mouse the user will be using in the operation of the computer. Alternatively, the computer manufacturer may provide two separate mouse buttons for each mouse.
Having a user preselect one of the two internal mice to be used inconveniences the user in two ways. First, the user must initially configure the computer through the SETUP program to select the mouse the user desires to use. Second, once the user has selected a mouse, the other mouse on the computer cannot be used, unless the user reconfigures the computer through the SETUP program. Clearly, providing the user the capability to use either mouse without having to reconfigure the computer through the SETUP program is desirable.
The alternative solution of providing separate switches for each mouse increases the manufacturing costs for the computer. Thus, in order to avoid increased manufacturing costs, an apparatus in which two mice share a pair of switches and enable a user to make a seamless transition to use either mouse at any time is desirable.